Cutting-nippers



(MOdel.)

S TAFT No. 496,584* GUTTING NIPPERS.

` Patented May 2 1893 Mmmmwwwwyxggggwww UNITED STATES PATENT OFFICE.

STEPHEN TAFT, OF MILLBURY, MASSACHUSETTS.

CUTTINGiNIPPERS.

SPECIFICATION forming part of Letters Patent No. 496,584, dated May 2,1893.

Application filed May 7, 1888. Serial No. 273,148. (Model.)

To all whom it may concern:

Beit known that I, STEPHEN TAET, a citizen of the United States,residing at Millbury, in the county of Worcester and State ot'Massachusetts, have invented certain new and useful Improvements inCutting-Nippers, of which the following is a specification, accompaniedby drawings forming a part of the Specication and showing a pair ofcuttingnippers embodying the essential features of my present invention,which relates to the form of the cutting-dies and to the method ofattaching them to the jaws of the nippers; also, to certain otherdetails of the construction of the cutting nippers, as hereinafterdescribed, and pointed out in the subjoined claims.

Figure 1 ofthe accompanying drawings represents a perspective view of apair of cutting nippers embodying my invention. Fig. 2 is a centrallongitudinal, sectional view on line X, X, Fig. 1, and Fig. 3 is anenlarged sectional view of the cutting dies and a portion of the jaws,on line Y, Y, Fig. 1.

Similar letters refer to similar parts in the several views.

A, A denote the jaws formed by the lateral extension of the levers A',A2. Each of the jaws A, A, is recessed by removing a rectangular cornerfrom the outer side of the jaws, the recess being bounded by the side c,parallel with the line of strain upon the edges of the dies in theoperation of cutting, and the side d at right angles thereto. The sidesc extend behind the cutting dies and form a seat for them and the sidesd act as shoulders to resist the direct thrust upon the edges of thedies.

Extending into the jaws A, A, at the intersection ot' the sides c and dare the mortises a, having their end walls concave as at f and the sidewalls slightly divergent from f, forming tapering mortises, one of saidside walls, however being in the saine plane with the seat c.

The cutting dies B consist of blocks filling the rectangular recess inthe jaws A, A, and having tongues b, which are slightly tapering in formand are provided with round or oonvex ends tting the concave ends fofthe mortises ct. The dies B are held in place by the elastic, taperingpins e, e, which are driven through holes in the jaws A and tongues b,said holes being not coincident but so arranged that as the pins ai'edriven in the tongues b will be drawn into the mortises and the dies Bare drawn firmly against the sides d; thereby producing a slightcurvature of the pins e, c, which is illustrated in an exaggerated formin Fig. 3. The two sides of the cutting edge are the same in each die,except that the sides are reversed, and consist of the curved sides Cand the straight side D, inclosing the acute angle between them whichforms the cutting edge of the die; the curved side forming the outerside of one of the dies and the inner side of the opposite die, thecutting edges are sharp enough to part the metal to be cut and insteadof approaching each other in the same plane as is usually the caseincutting nippers of the ordinary construction, they are placed in dierentplanes as indicated by the parallel lines l, 1 and 2, 2, Fig. 3. Whenthe cutting edges reach a common plane at right angles to the lines 1,1; 2, 2, their motion is limited by an adjustable screw E held in one ofthe handles A' and coming incontact with the handle A2.

As I place the cutting edges of the dies in different planes I cause themetal to be cut to be pressed in opposite directions, that upon theouter side of the cutting edges b eing pressed in the direction of thearrow 3, Fig. 3, and that upon the inner side of the cutting edges beingpressed in the direction of the arrow 4, and it will be observed thatthe curved side of the cutting edge is placed upon the side toward whichthe metal is pressed, and that the curved line at the angle forming thecutting edge is nearly or quite parallel with the lines 1, 1; 2, 2,thereby allowing the metal to be moved over the side of the die. actionof the cutting edges is similar to those cutting nippers having a shearcut and the action of the cutting edges in my improved nippers may besaid to .combine the action of both classes of cutting nippers, viz;those having a shear cut, so called, and those having a parting out, orin which the edges approach each other in the saine plane, and thecutting is accomplished by severing or parting the metal in a line atright angles to the line of This motion of the dies as they approacheach other 1n the operation of cutting.

The levers A and A2 are pivoted at h and the plvotal pin is extended andenlarged forming the plate j with one edge resting against the shoulderla of one of the jaws. The inner end of the metal to be cut is pressedagainst the plate j as the jaws are brought together, the plate forminga fulcrum to hold the inner end of the metal while it is being cut bythe cutting dies. The extension of the fulcrum p1n 1s not new as thesame feature formed the subject of the Letters Patent No. 351,478,granted to me on the 26th day of October, 1886, but in my improvedcutting nippers herein described the extension of the pivotal pin 1senlarged so as to receive even the shortest end which may be cut off bythe dies B, and th e pressure against the edge of the plate 1s recelvedupon the shoulder 7c. The lever handles A', A2 I reduce in weightwithout materially decreasing their strength by making them hollow or Ushaped by forming a groove H upon the inner sides of the handles, makingtwo ribs m, m, upon the inner side of the handles. l

In order to afford a broad bearing for the dles B, the tongues b arereduced in thickness to lncrease the sides d, the tongues b, beingrequired to simply hold the dies in place, allowlng the strain upon theedges of the cutting dies, which is exerted in a line parallel with thearrows 3, 4, Fig. 3, to be received upon the sides d, d. As the tonguesb are only of sufcient thickness to serve to retain the dies in place,it becomes necessary to relleve them of any transverse strain producedby a strain upon the edges ofthe cutting dies 1n a direction at rightangles to the arrows 3, 4, Fig. 3, which would cause a fracture of thetongues. This is accomplished by making the tongues slightly taperingand forming their ends round as at f, Figs. 2 and 3, and also by theyielding fastening eifected by the elastic pins e, e. Theoretically thedies B are firmly supported upon the sides c and d of the jaws and thetongues b are not moved in the operation of cutting, but in practice anunusual strain at right angles to the arrows 3, 4 will cause atransverse strain to be eX- erted upon the tongues b, which wouldproduce a fracture of the tongues, were it not for the construction asshown by which the tongues are capable of not only a slight movement outof their mortises, but also ofaslight movement about their rounded endsf, which would not be possible if their ends were square and fittedmortises having plane end walls with angular corners. The form of therecess in which the dies are placed provide the sides c and d, theformer at right angles to any lateral strain upon the cutting edges; andthe latter at right angles to the strain tially as described.

in cutting, exerted parallel with the arrows 3, 4, Fig. 3.

I am aware that cutting nippers have been made having jaws provided withmortises to receive tongues or tenons upon the cutting dies, by whichthe dies were heldin place, such I do not herein claim, neither do Iclaim broadly the employment of elastic pins as such have been employedin other cases for analogous purposes, but

What I claim as my invention, and desire to secure by Letters Patent,is-

1. In a pair of pivoted cutting nippers, the combination of jaws movingin an arc of a circle and having rectangular recesses in their opposingcorners bounded by the walls d, at right angles with the line of strainupon the cutting dies, and walls c, parallel with said line of strain,tapering mortises extending into said jaws from the inner corners ofsaid recesses and parallel with said side c, cutting dies fitting saidrectangular recesses and having tapering tenons entering said mortisesand provided with cutting jaws placed in the central section of saiddies and at one side of said tenons and elastic pins passing throughsaid jaws and said tenons whereby said tenons are allowed to yield asthe strain upon the cutting dies is changed from the Walls c, to thewalls d, and vice versa, sub stantially as described. Y

2. In a pair of cutting nippers, having cutting dies which approach eachother in an arc of a circle, the cutting dies B, B, each provided withcutting edges, the edge of one of said dies being included by a planesurface upon its inner side and by a concavev surface upon its outerside, and the other of said dies having a cutting edge included by aplane surface upon its outer side and aconcave surface upon itsinnerside, substantially as described.

3. In a pair of cutting nippers, the combination with the jaws, havingcutting edges which approach each other in an arc of a circle, one ofsaid jaws being provided with a shoulder lo, of the plate j, formed byan extension of the pivotal pin of the nippers and resting against theshoulder 7c, substantially as described.

4. In a pair of cutting nippers the combination of jaws A, provided withtapering mortises a, cutting dies B, having tapering tenons b, beveledand concave surfaces C, and D, inclosing cutting edges, a shoulder k,formed on one of said jaws and a plate J, formed by the extension-of thepivotal pin and resting against lsaid shoulder, substan- STEPHEN TAFT.Witnesses:

RUFUs B. FowLER,

CHAs. A. WHITNEY.

IIO

